179 lines
3.0 KiB
Plaintext
179 lines
3.0 KiB
Plaintext
; The OS/K Team licenses this file to you under the MIT license.
|
|
; See the LICENSE file in the project root for more information.
|
|
|
|
;
|
|
; typedef int (*PUTC)(int ch)
|
|
; int doprnt(PUTC putc, int n, const char *fmt, va_list ap)
|
|
;
|
|
doprnt:
|
|
push rbp
|
|
mov rbp, rsp
|
|
|
|
push r12, r13, r14
|
|
push r15, r16, r17
|
|
|
|
mov r12, ax2 ; fmt
|
|
mov r14, ax3 ; va_list
|
|
mov r15, ax1 ; n
|
|
mov r17, ax0 ; putc
|
|
nul r16 ; return value
|
|
|
|
.main_loop:
|
|
; find '%' or null-terminator
|
|
mov rcx, STRLEN_MAX
|
|
mov r13, r12
|
|
scasb r13, '%'
|
|
|
|
; everything below r13 is a regular character; print it
|
|
.print_regular:
|
|
beq r12, r13, .check_modf
|
|
|
|
call .doput, b[r12]
|
|
|
|
inc r12, 1
|
|
jmp .print_regular
|
|
|
|
.check_modf:
|
|
; did we find a '%' ?
|
|
; if not, then we found fmt's null-terminator; we're done
|
|
bne b[r12], '%', .epilogue
|
|
|
|
; we did find a modifier / '%'
|
|
mov rax, b[r12+1]
|
|
inc r12, 2
|
|
|
|
beq rax, 's', .modf_s
|
|
beq rax, 'c', .modf_c
|
|
beq rax, 'p', .modf_p
|
|
beq rax, 'x', .modf_x
|
|
beq rax, 'd', .modf_d
|
|
beq rax, 'o', .modf_o
|
|
beq rax, 'b', .modf_b
|
|
beq rax, '%', .modf_percent
|
|
|
|
; unrecognized
|
|
jmp .bad_modifier
|
|
|
|
.modf_s:
|
|
; get string address
|
|
mov r13, q[r14]
|
|
inc r14, 8
|
|
|
|
bzr r13, .nullstring
|
|
|
|
.print_string:
|
|
movzx ax0, b[r13]
|
|
bzr ax0, .main_loop
|
|
|
|
inc r13, 1
|
|
call .doput
|
|
|
|
jmp .print_string
|
|
|
|
.modf_c:
|
|
call .doput, q[r14]
|
|
inc r14, 8
|
|
|
|
jmp .main_loop
|
|
|
|
.modf_p:
|
|
call .doput, '0'
|
|
call .doput, 'x'
|
|
; Fallthrough
|
|
|
|
.modf_x:
|
|
mov ax2, 16
|
|
jmp .print_number
|
|
|
|
.modf_d:
|
|
mov ax2, 10
|
|
jmp .print_number
|
|
|
|
.modf_o:
|
|
mov ax2, 8
|
|
jmp .print_number
|
|
|
|
.modf_b:
|
|
mov ax2, 2
|
|
jmp .print_number
|
|
|
|
.print_number:
|
|
; allocate itoa conversion buffer
|
|
dec rsp, 80
|
|
mov r13, rsp
|
|
|
|
; assume modifier already set up ax2
|
|
call itoa, rsp, q[r14]
|
|
inc r14, 8
|
|
|
|
.print_itoa_buf:
|
|
movzx ax0, b[r13]
|
|
|
|
bzr ax0, .pib_end_loop
|
|
inc r13, 1
|
|
|
|
call .doput
|
|
jmp .print_itoa_buf
|
|
|
|
.pib_end_loop:
|
|
inc rsp, 80
|
|
jmp .main_loop
|
|
|
|
.modf_percent:
|
|
call .doput, '%'
|
|
jmp .main_loop
|
|
|
|
.bad_modifier:
|
|
; print "%?" to clearly indicate that something is wrong
|
|
call .doput, '%'
|
|
call .doput, '?'
|
|
|
|
jmp .main_loop
|
|
|
|
.nullstring:
|
|
; %s was passed a NULL
|
|
call .doput, '('
|
|
call .doput, 'n'
|
|
call .doput, 'u'
|
|
call .doput, 'l'
|
|
call .doput, 'l'
|
|
call .doput, ')'
|
|
|
|
jmp .main_loop
|
|
|
|
.epilogue:
|
|
mov rax, r16
|
|
|
|
pop r17, r16
|
|
pop r15, r14
|
|
pop r13, r12
|
|
|
|
leave
|
|
ret
|
|
;
|
|
; prints ax0
|
|
;
|
|
.doput:
|
|
; update print count
|
|
inc r16, 1
|
|
|
|
; if n==0, don't print
|
|
; we follow the C convention that sprintf()-like functions
|
|
; should return the number of characters that would have
|
|
; been printed/written if 'n' were big enough
|
|
bzr r15, .r
|
|
|
|
; decrement n and print
|
|
dec r15, 1
|
|
call r17
|
|
|
|
; did putc fail?
|
|
jraxz .r
|
|
|
|
; yes, so artificially set n=0
|
|
nul r15
|
|
|
|
.r:
|
|
ret
|
|
|